Electroreduction utilization integrated technology and device based on chemical absorption method

Abstract

The invention discloses an electroreduction utilization integrated technology and device based on a chemical absorption method, and belongs to the technical field of electrocatalytic reduction and carbon capture. Comprising a spraying type absorption tower, a water pump machine, a pool front buffer tank, an electrolytic pool and a pool rear buffer tank. According to the integrated system integrating a chemical absorption method and an electrochemical CO2 reduction technology, the overall process of CO2 resource utilization is simplified, desorption and conversion of CO2 can be carried out in situ in an electrolytic tank, a carbonized solution formed in the carbon capture process is continuously utilized, the defects of the chemical absorption method are overcome, and the carbon capture efficiency is improved. And a complete technical chain is constructed, so that compared with a mainstream CO2 capture-utilization (CCU) system, the system is more advanced, and efficient cooperative operation under the same time-space dimension is realized. According to the invention, the overall energy consumption and equipment cost of an integrated system are reduced fundamentally, and a CO2 adduct can be formed through induction of an organic amine intermediate product, so that a CO2 configuration is bent, and the overpotential of an electrochemical CO2 reduction reaction is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic reduction and carbon capture, and specifically relates to an integrated technology and device for electrocatalytic reduction based on a chemical absorption method. Background Art

[0002] Chemical absorption is a technology that separates CO2 from a gas mixture through chemical reactions. It plays an important role in improving CO2 capture efficiency, reducing costs and achieving the "dual carbon" goals. It is the most feasible post-combustion carbon capture technology and shows great prospects for industrial application.

[0003] As a typical chemical absorption method, ammonia decarbonization has many advantages that the traditional alcohol amine solution-monoethanolamine (MEA) absorption method does not have: strong CO2 absorption capacity, low absorption reaction heat, low corrosiveness, and not easily degraded by O2 in the flue gas. It is also low in price and helps to form an integrated system for cascaded energy utilization and integrated removal of multiple pollutants.

[0004] Ammonia-based decarbonization technology generally has problems such as low CO2 absorption rate, severe ammonia escape, and high desorption and regeneration energy consumption.

[0005] The mainstream CO2 capture-utilization (CCU) system is a type of CCU technology that focuses on achieving effective utilization of CO2 through integrated capture and conversion processes, effectively improving energy efficiency and reducing global carbon emissions.

[0006] The mainstream CCU system needs to complete the entire process of "capture-regeneration-separation" to obtain high-purity CO2 for subsequent catalytic reduction, but its energy consumption cost is high and the process is complex. Summary of the invention

[0007] In order to solve the above problems, the present invention further provides an integrated chemical absorption and electrochemical reduction (ICCU) technology and device.

[0008] The technical solution adopted by the present invention is:

[0009] An integrated technology and device for electro-reduction utilization based on chemical absorption method, comprising a spray absorption tower, and a water pump machine 1, a pre-pool buffer tank, an electrolytic cell, a post-pool buffer tank, and a water pump machine 2 which are sequentially connected to the rich liquid outlet at the bottom of the spray absorption tower through a hose; the outlet of the water pump machine 2 is connected back to the lean liquid inlet of the spray absorption tower through a hose.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The present invention simplifies the overall process of CO2 resource utilization by integrating chemical absorption and electrochemical reduction of CO2 technology into an integrated system, so that the desorption and conversion of CO2 can be carried out in situ in an electrolytic cell, and the carbonized liquid (rich in bicarbonate ions, HCO3 - ) for further utilization, thus making up for the shortcomings of the chemical absorption method and building a complete technical chain, which is more advanced than the mainstream CO2 capture-utilization (CCU) system and realizes efficient coordinated operation in the same space-time dimension. The present invention fundamentally reduces the overall energy consumption and equipment cost of the integrated system, and can induce the formation of CO2 adducts through organic amine intermediates, causing the CO2 configuration to bend, thereby reducing the overpotential of the electrochemical CO2 reduction reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the present invention;

[0013] Figure 2 is a cross-sectional view of a spray-type absorption tower of the present invention;

[0014] Figure 3 It is a schematic diagram of the structure of the electrolytic cell of the present invention;

[0015] Figure 4 It is a structural schematic diagram of the electrolytic cell of the present invention when there is no electrolytic cell cover plate;

[0016] Figure 5 is a cross-sectional view of the liquid flow at the bottom of the electrolytic cell of the present invention;

[0017] Figure 6 It is a schematic diagram of the structure of the electrolytic cell cover plate of the present invention;

[0018] Figure 7 It is a schematic diagram of the anode side housing structure of the present invention;

[0019] Figure 8 It is a schematic diagram of the cathode side housing structure of the present invention;

[0020] Fig. 9 It is a schematic diagram of the structure of the anode electrode plate of the present invention;

[0021] Fig.10 Schematic diagram of the cathode electrode plate structure of the present invention;

[0022] Fig.11The figure is a characteristic diagram of the electrocatalytic reduction of ammonium bicarbonate under the condition of no CO2 bubbling; wherein: (a) three-electrode experimental system; (b) is a schematic diagram of the mechanism of reducing NH4HCO3 to CO2 by Ag-based catalyst modified by Br element; (c) is the result of halogen element enhanced electrocatalytic reduction of NH4HCO3; (d) is a comparison diagram of CO Faraday efficiency before and after Br element modification; (e) is a Tafel diagram of Ag catalyst modified by trace Br;

[0023] Fig.12 It is a structure-activity relationship diagram between the structural composition of metal-based catalysts and the electrocatalytic selective reduction of CO2; wherein: (a) is the Ce-Cu electrode catalyzing the reduction of CO2 to C2H4; (b) is the synthesis process of the Au-CNT catalytic electrode; (c) is the Vo-SnO2 electrode catalyzing the reduction of CO2 to HCOOH; (d) is the DFT calculation result of the intermediate free energy of the Vo-SnO2 electrode catalyzing the CO2 reduction process; (e) is the effect of the Au-CNT catalytic electrode on improving the CO2 reduction selectivity;

[0024] Among them: 1. Spray absorption tower; 2. Water pump 1; 3. Buffer tank before the cell; 4. Electrolytic cell; 5. Buffer tank after the cell; 6. Hose; 7. Top cover of the tower; 8. Flue gas outlet; 9. Top demisting layer; 10. Liquid distributor; 11. Lean liquid inlet; 12. Upper filler; 13. Liquid redistributor; 14. Lower filler; 15. Bottom cover of the tower; 16. Flue gas inlet; 17. Rich liquid outlet at the bottom of the tower; 18. Electrolyte inlet; 19. Electrolyte outlet; 20. Anode side shell; 21. Cathode side shell; 22. Electrolyte The cell cover; 23. Reduction gas outlet; 24. Water pump unit 2; 25. Fasteners; 26. Anode chamber; 27. Anode chamber side wall pipeline; 28. Ion exchange membrane; 29. ​​Partition chamber; 30. Partition plate channel; 31. Cathode chamber side wall pipeline; 34. Cathode chamber; 35. Partition plate; 36. Joint; 37. Membrane gap; 38. Cathode electrode port; 39. Anode electrode port; 40. Oxygen outlet; 41. Cathode electrode plate; 42. Cathode joint; 43. Electrode plate channel; 44. Anode electrode plate; 45. Anode joint. DETAILED DESCRIPTION

[0025] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0026] The present invention relates to an integrated system design for post-combustion carbon capture and utilization, and specifically to the development of a system-integrated technical device for absorbing carbon dioxide (CO2) into a carbonized liquid through a chemical absorbent after combustion and then electrolytically reducing it into energy-based reduction products such as C1 and C2 using an electrolytic cell equipped with a catalyst.

[0027] The chemical absorbent of the present invention is any chemical absorbent that has CO2 absorption capacity and can promote the formation of bicarbonate ions (HCO3-) during the absorption process;

[0028] As a typical example of chemical absorbent, amine solution can effectively capture CO2 by generating bicarbonate or carbonate. Specifically, the scope of amine solution covers a series of common solvent components widely adopted by the industry, such as MEA (monoethanolamine), DEA (diethanolamine), MDEA (methyldiethanolamine) and DIPA (diisopropanolamine).

[0029] The catalyst of the present invention can be any catalyst that can promote the catalytic conversion of CO2 and HCO3- into carbon-containing reducing liquid (such as methanol, formic acid) and reducing gas (such as carbon monoxide, methane) in the electrolytic cell, such as: a) metal and its oxide derivative catalyst: copper (Cu), silver (Ag), copper oxide (CuO), cuprous oxide (Cu2O), etc.;

[0030] b) Alloy catalyst: Cu-Sn alloy, Au-Pb alloy, etc.;

[0031] c) Transition metal nitrides and phosphides: nitrides and phosphides of molybdenum (Mo), cobalt (Co), nickel (Ni), etc.;

[0032] d) Nanostructured materials: metal nanoparticles deposited on carbon nanotubes (CNTs), graphene and two-dimensional layered materials;

[0033] e) Organic and hybrid catalysts: conjugated microporous polymers (CMPs), porphyrin and phthalocyanine derivatives, organic metal frameworks (OMFs) and metal-organic frameworks (MOFs), etc.;

[0034] f) Semiconductor materials: CdS, CdSe, ZnO, TiO2 and other photocatalysts.

[0035] like Figure 1 As shown, the present invention provides an integrated technology and device for electro-reduction utilization based on chemical absorption method, including a spray absorption tower 1, and a water pump 2, a pre-pool buffer tank 3, an electrolytic cell 4, a post-pool buffer tank 5, and a water pump 24, which are sequentially connected to the rich liquid outlet 17 at the bottom of the spray absorption tower 1 through a hose 6; the outlet of the water pump 24 is connected back to the lean liquid inlet 11 of the spray absorption tower 1 through a hose 6.

[0036] The steps for constructing the integrated device are as follows:

[0037] Step 1: construct a spray absorption tower 1, wherein the top and bottom ends of the spray absorption tower 1 are provided with inlets and outlets for electrolyte circulation, and the rich liquid outlet 17 at the bottom of the spray absorption tower 1 is connected with a hose 6;

[0038] Step 2: Connect the hose 6 obtained in step 1 to the water inlet of the water pump 2, and then continue to connect the water outlet of the water pump 2 to the hose 6;

[0039] Step 3: Connect the hose 6 obtained in step 2 to the liquid inlet on the bottom side of the pre-pool buffer tank 3, and then connect the liquid outlet on the top side of the pre-pool buffer tank 3 to the hose 6;

[0040] Step 4: Connect the hose 6 obtained in step 3 to the electrolyte inlet 18 on the bottom side of the integrated electrolytic cell 4 (here is a schematic diagram of a single electrolytic cell of the integrated electrolytic cell 4), then connect the electrolyte outlet 19 of the integrated electrolytic cell 4 to the hose 6, and connect the oxygen outlet 40 and the reducing gas outlet 23 on the top side of the integrated electrolytic cell 4 to the oxygen storage system and the reducing gas storage system respectively;

[0041] Step 5: Connect the hose 6 obtained in step 4 to the separation liquid inlet on the bottom side of the post-pool buffer tank 5, then connect it from the top of the post-pool buffer tank 5 to the hose 6, and connect the reduction liquid outlet at the bottom of the post-pool buffer tank 5 to the reduction liquid storage system;

[0042] Step 6: Connect the hose 6 obtained in step 5 to the water inlet of the second water pump 24, and then connect the water outlet of the second water pump 24 to the hose 6;

[0043] Step 7: Connect the hose 6 obtained in step 6 to the lean liquid inlet 11 on the top side of the spray absorption tower 1.

[0044] By gradually building in the order of the above seven steps, the ICCU system of the present invention can be completed. Figure 1 .

[0045] The ICCU system assembled by the above method can be used as an energy conversion device for post-combustion carbon capture and resource recycling, which can convert the excess electricity sent by the renewable energy power grid into combustible gas and alcohol liquid for storage, forming the core hub of source, grid, load and storage.

[0046] like Figure 2 As shown, the spray absorption tower 1 includes a tower top cover 7, a liquid distributor 10, an upper filler 12, a liquid redistributor 13, a lower filler 14, a tower bottom cover 15, a lower filler layer cylinder, a middle cylinder, an upper filler layer cylinder and a top cylinder;

[0047] The tower bottom cover 15 is installed on the bracket, and the lower packing layer cylinder, the middle cylinder, the upper packing layer cylinder, the top cylinder, and the tower top cover 7 are installed on the tower bottom cover 15 in order from bottom to top.

[0048] The bottom cover 15 and the lower packing layer cylinder, the lower packing layer cylinder and the middle cylinder, the middle cylinder and the upper packing layer cylinder, the upper packing layer cylinder and the top cylinder, and the top cylinder and the top cover 7 are all butted against each other through the inner concave joint 36.

[0049] A flue gas inlet 16 is provided on the side of the tower bottom cover 15, a tower bottom rich liquid outlet 17 is provided at the bottom of the tower bottom cover 15, a lower filler 14 is filled in the lower filler layer cylinder, a liquid redistributor 13 is fixedly installed in the middle cylinder, an upper filler 12 is filled in the upper filler layer cylinder, a liquid distributor 10 is fixedly installed in the top cylinder, a lean liquid inlet 11 is provided on the top cylinder, and the lean liquid inlet 11 is connected to the liquid distributor 10, a top demisting layer 9 is installed in the tower top cover 7, and a flue gas outlet 8 is provided on the top of the tower top cover 7.

[0050] The spray absorption tower 1 is constructed from bottom to top, including the following steps:

[0051] Step 1: First, install the tower bottom cover 15 on the bracket, then connect the lower packing layer cylinder to the tower bottom cover 15 along the joint 36 according to the inner concave joint 36, then use screws to reinforce the outer periphery of the joint 36 between the lower packing cylinder and the tower bottom cover 15, and finally evenly pour the lower packing 14 onto the grid plate at the bottom of the lower cylinder;

[0052] Step 2: Based on step 1, the middle cylinder is installed on the lower packing cylinder along the joint 36, and then the liquid redistributor 13 is fixed to the inner wall of the middle cylinder, and finally fastened with screws on the outside of the joint 36;

[0053] Step 3: On the basis of step 2, the upper filling layer cylinder is installed on the middle cylinder along the joint 36, and then the outer periphery of the joint 36 between the upper filling cylinder and the middle cylinder is reinforced with screws, and finally the upper filling 12 is evenly poured onto the grid plate at the bottom of the upper cylinder;

[0054] Step 4: Based on step 3, install the top cylinder onto the upper packing cylinder along the joint 36, then fix the liquid distributor 10 on the inner wall of the top cylinder, and finally fasten it with screws on the outside of the joint 36;

[0055] Step 5: On the basis of step 4, the tower top cover 7 is installed on the upper cylinder along the joint 36, and then the outer periphery of the joint 36 between the tower top cover 7 and the top cylinder is reinforced with screws;

[0056] The present invention adopts a design of a convex-upper-concave-lower joint 36 between the lower packing layer cylinder, the middle cylinder, the upper packing layer cylinder, the top cylinder, the tower top cover 7 and the tower bottom cover 15. Compared with the traditional flat seam connection, it has the following advantages: 1. The joint 36 is more stable and convenient when the two devices are connected, and it is more convenient for later fastening; 2. The liquid will not seep out from the joint 36 during the process of spraying and flowing from top to bottom, which is beneficial to the maintenance of the absorption tower and the stability of the surrounding environment; 3. When the gas flows from bottom to top, it will seep out less from the joint 36, which is beneficial to the full absorption of the flue gas and the external maintenance of environmental stability.

[0057] like Figures 3 to 10 As shown, the electrolytic cell 4 includes a shell, an electrolyte inlet 18, an electrolyte outlet 19, an anode electrode plate 44, a cathode electrode plate 41 and an ion exchange membrane 28; the right side surface of the lower end of the shell is provided with an electrolyte inlet 18 and an electrolyte outlet 19, and the electrolyte inlet 18 and the electrolyte outlet 19 are arranged front and back, and a plurality of anode electrode plates 44 and cathode electrode plates 41 are arranged crosswise from right to left and installed in the shell, and the anode connector 45 of the anode electrode plate 44 and the cathode connector 42 of the cathode electrode plate 41 respectively pass through the shell, and the rear end of the anode electrode plate 44 and the front end of the cathode electrode plate 41 are provided with vertically arranged electrode plate channels 43, and an ion exchange membrane 28 is arranged between adjacent anode electrode plates 44 and cathode electrode plates 41, and the ion exchange membrane 28 is higher than the anode electrode plate 44 and the cathode electrode plate 41, and forms a closed space with the adjacent ion exchange membrane 28;

[0058] The front side wall of the housing is provided with a plurality of anode chamber side wall pipes 27 from right to left in sequence, the inlet of each anode chamber side wall pipe 27 being arranged on the left side of the corresponding anode electrode plate 44, and the outlet of each anode chamber side wall pipe 27 being arranged on the right side of the next anode electrode plate 44;

[0059] A partition plate 35 is installed on the left side of the outermost cathode electrode plate 41. The chamber between the partition plate 35 and the shell is a partition chamber 29. A partition plate channel 30 is provided at the rear side of the partition plate 35 for connecting the anode chamber 26 and the cathode chamber 34.

[0060] The rear side wall of the housing is provided with a plurality of cathode chamber side wall pipes 31 from left to right, the inlet of each cathode chamber side wall pipe 31 is arranged on the right side of the corresponding cathode electrode plate 41, and the outlet of each cathode chamber side wall pipe 31 is arranged on the left side of the next cathode electrode plate 41;

[0061] From right to left, the anode chamber 26 is between the shell and the nearest ion exchange membrane 28, followed by the cathode chamber 34 and the anode chamber 26 arranged alternately between the two ion exchange membranes 28, and finally the cathode chamber 34 is between the leftmost ion exchange membrane 28 and the partition plate 35;

[0062] According to the gravity direction, the anode chamber 26 and the cathode chamber 34 have the anode gas chamber and the cathode gas chamber on the upper side and the anode liquid chamber and the cathode liquid chamber on the lower side. The anode gas chamber is provided with an oxygen outlet 40 and the cathode gas chamber is provided with a reducing gas outlet 23.

[0063] The electrolyte can immerse the anode electrode plate 44 and the cathode electrode plate 41, but will not be higher than the bottom of the oxygen outlet 40 and the reducing gas outlet 23. At the same time, the oxygen outlet 40 and the reducing gas outlet 23 are at the top of the electrolytic cell 4 shell.

[0064] like Figure 3 As shown, the shell includes an anode side shell 20, a cathode side shell 21 and an electrolytic cell cover 22; the anode side shell 20 and the cathode side shell 21 are butted together front to back, and the electrolytic cell cover 22 sealing cover is installed on the anode side shell 20 and the cathode side shell 21, and the anode side shell 20, the cathode side shell 21 and the electrolytic cell cover 22 are butted together through an inner recessed seam 36 when they are connected to each other.

[0065] like Figures 3 to 10 As shown, a plurality of anode electrode openings 39 are provided on the front side wall of the anode side housing 20, a plurality of cathode electrode openings 38 are provided on the rear side wall of the cathode side housing 21, an anode connector 45 is provided at one end of the anode electrode plate 44, and an electrode plate channel 43 is provided at the other end, the anode connector 45 of the anode electrode plate 44 passes through the anode electrode opening 39, a cathode connector 42 is provided at one end of the cathode electrode plate 41, and an electrode plate channel 43 is provided at the other end, the cathode connector 42 of the cathode electrode plate 41 passes through the cathode electrode opening 38, the anode connector 45 is connected to the anode of an external pulse power supply, and the cathode connector 42 is connected to the cathode of the external pulse power supply.

[0066] like Figures 4 to 6 As shown, corresponding to the front, back and upper sides of each ion exchange membrane 28, a plurality of membrane slits 37 are opened on the anode side housing 20, the cathode side housing 21 and the electrolytic cell cover plate 22.

[0067] like Figure 3 , Figure 4 As shown, the anode side housing 20 , the cathode side housing 21 and the electrolytic cell cover plate 22 are all connected by fasteners 25 .

[0068] The construction method of the single electrolytic cell 4 of the integrated electrolytic cell includes the following steps:

[0069] Step 1: insert the anode connector 45 on the anode electrode plate 44 and the cathode connector 42 of the cathode electrode plate 41 into the anode electrode port 39 of the anode side housing 20 and the cathode electrode port 38 of the cathode side housing 21 respectively;

[0070] Step 2: Based on step 1, the anode side housing 20 and the cathode side housing 21 are joined together along the opening and closing of the seam 36;

[0071] Step 3: Based on step 2, the ion exchange membranes 28 are inserted one by one along the membrane gaps 37;

[0072] Step 4: On the basis of step 3, the electrolytic cell cover plate 22 is installed from top to bottom along the joint 36 to the joint 36 of the anode side housing 20 and the cathode side housing 21;

[0073] Step 5: Based on step 4, tighten the threaded mouth of the fastener 25 with screws, etc., then connect the anode of the external pulse power supply to the anode terminal 45 of the electrolytic cell, and then connect the cathode of the external pulse power supply to the cathode terminal 45 of the electrolytic cell.

[0074] By installing the above five steps in sequence, the single electrolytic cell 4 of the integrated electrolytic cell of the present invention can be stably completed, and then the integrated electrolytic cell can be formed by only connecting the single electrolytic cells 4 in parallel.

[0075] Compared with the prior art, the present invention has the following advantages in terms of electrolytic cell installation:

[0076] 1. The present invention uses a seam 36 treatment at the overlapping surfaces of the anode side shell 20, the cathode side shell 21 and the electrolytic cell cover 22. This treatment method makes the integrity of the electrolytic cell 4 better after forming, and reduces the probability of adverse phenomena such as leakage and gas leakage;

[0077] 2. The present invention fixes the spatial position of the ion exchange membrane 28 by inserting the ion exchange membrane 28 into the membrane gap 37, effectively fixes the position of the ion exchange membrane 28, and effectively separates the cathode chamber 34 from the anode chamber 26 and the cathode gas chamber from the anode gas chamber, thereby avoiding the disordered mixing between gas phase products and liquid phase products, and avoiding the undesirable phenomenon that the cathode reduction product is close to the anode plate and undergoes oxidation reaction to reduce the yield, which is beneficial to the subsequent product separation and rich liquid regeneration treatment;

[0078] The system operation of the present invention is operated through the following technical process: comprising the following steps:

[0079] Step 1, the factory flue gas enters the bottom cover 15 of the absorption tower through the flue gas inlet 16 on the side of the bottom cover of the spray absorption tower 1, flows from bottom to top, successively passes through the lower packing layer 14, the middle liquid redistributor 13, the upper packing layer 12, the upper liquid distributor 10 and the top demisting layer 9, reaches the inside of the top cover 7 of the spray absorption tower, and then flows out from the top flue gas outlet 8 to discharge the flue gas that has reached the emission standard. The electrolyte lean liquid flows into the upper part of the spray absorption tower from the lean liquid inlet 11, and is evenly sprayed from the upper liquid distributor 10 to the upper packing layer 12. The lean liquid evenly wets the surface of the packing, and then flows downward into the liquid redistributor 13, is collected by the liquid redistributor 13 and evenly sprayed again to the lower packing layer 14, and the spray continues to wet the surface of the packing and then flows downward into the bottom cover 15 of the spray absorption tower, and finally forms an electrolyte rich liquid that flows out from the rich liquid outlet at the bottom of the tower. During this period, the flue gas passes through the gaps between the packing and the gaps between the components from bottom to top, and the CO2 in the flue gas is absorbed by the surface of the packing and the chemical absorbent (ammonia water) in the sprayed electrolyte lean solution. For details, see Figure 2 ;

[0080] Step 2: Use a water pump 2 to pump the electrolyte rich liquid obtained in step 1 into the pre-cell buffer tank 3 for storage, and buffer the carbonization degree of the carbonized liquid in the rich liquid to a suitable range. Subsequently, the carbonized liquid rich liquid flows out of the pre-cell buffer tank 3 and flows into the electrolyte inlet 18 integrated into the electrolytic cell 4;

[0081] Step 3: The electrolyte introduced from the electrolyte inlet 18 is guided to the positive liquid chamber 26. After a pulse current is introduced externally, the electrolyte undergoes an intermittent oxidation reaction on the surface of the anode electrode plate 44 to generate O2 and H + , O2 enters the gas chamber from the liquid chamber of the anode chamber 26, and the gas chamber is connected to the oxygen storage system, H + The electrolyte passes through the ion exchange membrane 28 and enters the liquid chamber of the cathode chamber 34 to achieve charge balance. Driven by the liquid flow, the electrolyte flows through the anode chamber 26, the electrode plate channel 43, the next anode chamber 26, the anode chamber side wall pipe 27, the compartment 29 and the compartment plate channel 30 to enter the cathode chamber 34. Subsequently, the CO3 in the electrolyte - A balanced exchange phenomenon occurs near the surface of the cathode electrode plate, CO2 is generated and adsorbed on the surface of the cathode electrode plate 41, and then a reduction reaction occurs intermittently under the action of an external pulse current to generate C + and H2 and other gas-liquid reduction products. H2 and gas-phase reduction products enter the gas chamber from the liquid chamber of the cathode chamber 34, and the gas chamber is connected to the reduction gas storage chamber. The electrolyte after the reduction reaction continues to flow through the electrode plate channel 43, the cathode chamber 34, the cathode chamber side wall pipe 31, the next cathode chamber 34, and finally flows out from the electrolyte outlet 19 to generate a mixed liquid of electrolyte lean liquid and alcohol liquid-phase reduction products;

[0082] Step 4: Pass the mixed liquid obtained in step 3 into the post-cell buffer tank 5, and finally separate the mixed liquid into electrolyte lean liquid and alcohol liquid phase reduction product after the sieving effect of the molecular sieve in the tank. The separated electrolyte lean liquid flows out from the regeneration liquid outlet at the top of the post-cell buffer tank to form regeneration liquid, and the separated alcohol liquid phase reduction product flows out from the reduction liquid outlet at the bottom of the post-cell buffer tank 5 and flows into the reduction liquid phase product storage system.

[0083] Step 5, the regeneration liquid obtained in step 4 is conveyed under pressure by the water pump 24, and flows into the interior of the spray absorption tower 1 through the lean liquid inlet 11 of the spray absorption tower 1.

[0084] The continuous cycle of the above five steps constitutes the sustainable reflux process of the ICCU system. Compared with the prior art, the present invention has the following advantages:

[0085] (1) The present invention combines the spray absorption tower with the integrated electrolytic cell 4 by means of system integration, and comprehensively utilizes the multiple technical features of the spray absorption tower for separating flue gas, the chemical absorbent (ammonia water) for chemical absorption of CO2, and the electrolytic cell for electrochemical reduction of CO2, thereby developing a complete ICCU system;

[0086] (2) The number of integrated electrolytic cells 4 of the present invention can be increased or decreased according to the actual production cycle benefits, which is very suitable for industrial large-scale operation control;

[0087] (3) The flow paths of the electrolyte in the cathode chamber 34 and the anode chamber 26 of the single electrolytic cell 4 of the present invention are interconnected. Compared with the conventional electrolytic cell in which the cathode chamber 34 and the anode chamber 26 are not interconnected, the electrolytic cell 4 designed in the present invention has a compartment 29 on the opposite side of the electrolyte. The electrolyte flows from the electrolyte inlet 18 into the anode chamber 26, flows into the cathode chamber 34 after passing through the compartment 29, and then flows out of the cathode chamber 34 from the electrolyte outlet 19, thereby achieving full reduction of the electrolyte, thereby improving the overall efficiency of electroreduction and the efficiency of rich liquid regeneration. In the conventional electrolytic cell, only the electrolyte in the cathode chamber can participate in the reduction reaction of the electrode.

[0088] (4) The electrolyte flow direction of a single electrolytic cell 4 of the present invention is single, and can only flow from the anode chamber 26 to the cathode chamber 34, thereby ensuring that the alcohol liquid phase reduction products generated after the reduction reaction in the electrolyte will not enter the anode chamber 26, thereby causing the reduction products to be oxidized, thereby ensuring the normal output of the alcohol liquid phase reduction products.

[0089] Embodiment 1:

[0090] The inventor and his team studied the structure-activity relationship between the structural composition of the catalytic electrode and the reduction characteristics of ammonium bicarbonate under the condition of no CO2 bubbling. The three-electrode experimental system used for online gas phase product monitoring is as follows Fig.11 a. The results show that the Ag catalyst modified by halogen elements can promote the process of ammonium bicarbonate reduction to generate CO ( Fig.11 c), among which the effect of Br modification is more significant ( Fig.11 b, d). The modification effect of Br mainly comes from the inhibition of proton adsorption and hydrogen evolution reaction on the electrode surface. The fundamental reason is that Br changes the electronic state and structure of the Ag substrate and forms a chemical bond with Ag in the Helmholtz plane. In addition, trace Br on the Ag substrate also has a positive contribution to the electrochemical reduction selectivity and catalytic activity of ammonium bicarbonate, providing a theoretical basis and experimental guarantee for exploring the mechanism of the influence of catalyst surface morphology on CO2 reduction reaction in this project invention. The Tafel diagram of the trace Br-modified Ag catalyst shows that the carbon source actually involved in the reduction reaction is CO2 gas produced by the decomposition of NH4HCO3 rather than bicarbonate ions ( Fig.11 e) To provide theoretical support for exploring the dynamic equilibrium mechanism and kinetic characteristics between bicarbonate and CO2 in this project.

[0091] Embodiment 2:

[0092] The inventor and his team have previously conducted a series of studies on the mechanism by which the structural composition of metal-coupled catalysts or modified metal catalysts affects the electrocatalytic selective reduction of CO2. Since current research shows that the reduction process of bicarbonate is likely to start with equilibrium conversion to CO2, that is, the reactant actually involved in the reduction process is CO2, the research results on the selective characteristics of CO2 reduction can be used to guide the study of the reduction process of ammonium bicarbonate. The inventor and his team have developed a series of catalytic electrodes with high selective activity based on metal-based catalysts, including Ce-Cu catalytic electrodes, Au-CNT catalytic electrodes, Vo-SnO2 catalytic electrodes, Cu-Bi catalytic electrodes, etc. (some results are shown in Figure 2). Fig.12 a~c). Among them, the black porous SnO2 nanoelectrode showed high reactivity and selectivity for the reduction of CO2 to formate. DFT calculations further revealed the mechanism by which the introduction of oxygen vacancies can reduce the adsorption energy of intermediates and promote the selective reduction of CO2 to formate ( Fig.12d); Provide theoretical basis and experimental guarantee for exploring the competitive reaction regulation mechanism of electrocatalytic ammonium bicarbonate to generate liquid products in this project. The synthetic process of metal complex reconstruction on appropriate carriers induces charge transfer between gold nanoclusters and carbon nanotubes, forming a relatively electron-rich state of gold active sites, which greatly promotes the selective activation process of CO2; Provide theoretical support and experimental basis for exploring the real active sites of functional carbon material carriers participating in the reaction in this project ( Fig.12 e).

[0093] The present invention adopts chemical absorption carbon capture technology, which has high carbon capture efficiency, stable temperature control, large carbon capture capacity, and the product is directly used for subsequent reactions, reducing the temperature loss caused by NH4HCO3 phase change recovery;

[0094] The present invention adopts electrochemical reduction of CO2 technology, utilizing the property of the integrated electrolytic cell 4 working at room temperature to electrochemically reduce CO2, and is suitable for large-scale commercial operation;

[0095] The number of the integrated electrolytic cells 4 of the present invention can be configured according to actual conditions, and can well adapt to the peak and low peak of the power grid. The energy storage thereof has a large adjustable range and strong operability.

[0096] The spray absorption tower 1 of the present invention uses a liquid redistributor 13, which can collect the absorption liquid flowing down from the upper filler and evenly distribute it to the lower filler, thus avoiding the undesirable situation of uneven liquid distribution caused by an overly long filler layer and filler blockage;

[0097] The type of CO2 absorbing liquid of the present invention is an amine substance, which has the ability to absorb CO2 efficiently, but is not limited to amine substances;

[0098] The working environment of the electrode is a normal temperature environment, and the electrolyte can flow from the anode chamber 26 to the cathode chamber 34, preventing the cathode product from flowing to the anode plate and causing an oxidation reaction;

[0099] The shell of the single electrolytic cell 4 of the present invention has seams 36, and the corresponding seams 36 can fit perfectly, reducing the risk of liquid leakage and gas leakage;

[0100] The anode side electrolytic cell shell 20 of the integrated electrolytic cell 4 of the present invention is provided with an anode chamber side wall pipeline 27, and the cathode side electrolytic cell shell 21 is provided with a cathode chamber side wall pipeline 31, so as to facilitate opening the electrolyte flow pipelines of the two anode chambers 26 and the two cathode chambers 34;

[0101] The integrated electrolytic cell 4 of the present invention is provided with a compartment 29 between the cathode chamber 34 and the anode chamber 26, which increases the spatial distance between the anode chamber 26 and the cathode chamber 34, and prevents the alcohol liquid phase product in the cathode chamber 34 from flowing back to the anode chamber 26, thereby ensuring the stable generation of alcohol reduction products;

[0102] The anode plate 44 and cathode plate 41 of the integrated electrolytic cell 4 of the present invention respectively contain electrode plate channels 43 on the opposite sides of the anode connector 42 and cathode connector 45, which facilitate the electrolyte to flow from one side of the electrode plate to the other side, extend the electrolysis distance of the electrolyte, and allow the electrolyte to be fully electrolyzed;

[0103] The pH value of the electrolyte needs to be maintained in the range of 8 to 9.

[0104] The present invention combines the respective advantages of chemical absorption of CO2 in the absorption tower and electrochemical reduction of CO2 in the integrated electrolytic cell, uses chemical absorbents such as ammonia water as the basic absorption liquid, and regulates parameters such as the concentration of the chemical absorbent (ammonia water), absorption temperature, carbon dioxide concentration, and pulse current to achieve the cyclic conversion of the absorption liquid and the electrolyte, thereby achieving the dual carbon goals of cyclic carbon capture, carbon reduction, and carbon storage in the ICCU system, fundamentally solving the problem of complex electrolyte sources and the lack of an integrated system. The technology and device of integrated chemical absorption electroreduction utilization (ICCU) developed by the present invention can operate in a highly efficient and sustainable cycle; under the premise that the system parameters are properly configured, no external absorption liquid (electrolyte lean liquid) is required during the operation of the system; the equipment belongs to post-combustion carbon capture equipment, so there is no need to modify the building structure of the flue gas emission facilities in factories and other places, and the installation can be completed by adding the device of the invention at the appropriate flue gas emission position later; the spray absorption tower and the shell structure of the integrated electrolytic cell of the equipment are both treated with seams 36, which are not easy to leak the internal gas and liquid, and are very friendly to the ecological environment; the gas-liquid phase reduction material produced by the invention can be separated and used as a reserve raw material for energy, which is beneficial to ensuring the country's energy security.

[0105] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. An integrated technology and device for electroreduction based on chemical absorption method, characterized in that: The invention comprises a spray-type absorption tower (1), and a water pump (2), a pre-pool buffer tank (3), an electrolytic cell (4), a post-pool buffer tank (5), and a water pump (24) which are sequentially connected to a rich liquid outlet (17) at the bottom of the spray-type absorption tower (1) through a hose (6); the water outlet of the water pump (24) is connected back to a lean liquid inlet (11) of the spray-type absorption tower (1) through a hose (6).

2. The integrated technology and device for utilizing electroreduction by chemical absorption method according to claim 1, characterized in that: The spray absorption tower (1) comprises a tower top cover (7), a liquid distributor (10), an upper filler (12), a liquid redistributor (13), a lower filler (14), a tower bottom cover (15), a lower filler layer cylinder, a middle cylinder, an upper filler layer cylinder and a top cylinder; The tower bottom cover (15) is mounted on a bracket, and a lower packing layer cylinder, a middle cylinder, an upper packing layer cylinder, a top cylinder, and a tower top cover (7) are sequentially mounted on the tower bottom cover (15) from bottom to top. The tower bottom cover (15) and the lower packing layer cylinder, the lower packing layer cylinder and the middle cylinder, the middle cylinder and the upper packing layer cylinder, the upper packing layer cylinder and the top cylinder, and the top cylinder and the tower top cover (7) are all butted against each other via an inner concave joint (36). A flue gas inlet (16) is provided on the side of the tower bottom cover (15), a tower bottom rich liquid outlet (17) is provided at the bottom of the tower bottom cover (15), a lower packing (14) is filled in the lower packing layer cylinder, a liquid redistributor (13) is fixedly installed in the middle packing layer cylinder, an upper packing (12) is filled in the upper packing layer cylinder, a liquid distributor (10) is fixedly installed in the top packing layer cylinder, a lean liquid inlet (11) is provided on the top packing layer cylinder, and the lean liquid inlet (11) is connected to the liquid distributor (10), a top demisting layer (9) is installed in the tower top cover (7), and a flue gas outlet (8) is provided at the top of the tower top cover (7).

3. The integrated technology and device for electroreduction based on chemical absorption method according to claim 1, characterized in that: The electrolytic cell (4) comprises a shell, an electrolyte inlet (18), an electrolyte outlet (19), an anode electrode plate (44), a cathode electrode plate (41) and an ion exchange membrane (28); the right side surface of the lower end of the shell is provided with an electrolyte inlet (18) and an electrolyte outlet (19), and the electrolyte inlet (18) and the electrolyte outlet (19) are arranged front and back, and a plurality of anode electrode plates (44) and cathode electrode plates (41) are arranged crosswise from right to left in the shell, and the anode electrode plates (44) are arranged crosswise from right to left in the shell. 4) and the cathode connector (42) of the cathode electrode plate (41) are respectively passed through the shell, the rear end of the anode electrode plate (44) and the front end of the cathode electrode plate (41) are provided with vertically arranged electrode plate channels (43), an ion exchange membrane (28) is provided between adjacent anode electrode plates (44) and cathode electrode plates (41), and the ion exchange membrane (28) is higher than the anode electrode plate (44) and the cathode electrode plate (41), and forms a closed space with the adjacent ion exchange membrane (28); The front side wall of the housing is provided with a plurality of anode chamber side wall pipes (27) in sequence from right to left, the inlet of each anode chamber side wall pipe (27) being arranged on the left side of the corresponding anode electrode plate (44), and the outlet of each anode chamber side wall pipe (27) being arranged on the right side of the next anode electrode plate (44); A partition plate (35) is installed on the left side of the outermost cathode electrode plate (41); the chamber between the partition plate (35) and the shell is a partition chamber (29); and the partition plate (35) is provided with a plurality of partition plate channels (30) at the end of the cathode side shell (21) for connecting the anode chamber (26) and the cathode chamber (34); The rear side wall of the housing is provided with a plurality of cathode chamber side wall pipes (31) in sequence from left to right, the inlet of each cathode chamber side wall pipe (31) being arranged on the right side of the corresponding cathode electrode plate (41), and the outlet of each cathode chamber side wall pipe (31) being arranged on the left side of the next cathode electrode plate (41); From right to left, the anode chamber (26) is between the shell and the nearest ion exchange membrane (28), followed by the cathode chamber (34) and the anode chamber (26) alternately arranged between the two ion exchange membranes (28), and finally the cathode chamber (34) is between the leftmost ion exchange membrane (28) and the partition plate (35); the anode chamber (26) and the cathode chamber (34) are arranged in the direction of gravity, with the anode gas chamber and the cathode gas chamber on the upper side and the anode liquid chamber and the cathode liquid chamber on the lower side. The anode gas chamber is provided with an oxygen outlet (40), and the cathode gas chamber is provided with a reducing gas outlet (23).

4. The integrated technology and device for electroreduction based on chemical absorption method according to claim 3, characterized in that: The shell comprises an anode side shell (20), a cathode side shell (21) and an electrolytic cell cover plate (22); the anode side shell (20) and the cathode side shell (21) are butted together front and back, the electrolytic cell cover plate (22) sealing cover is mounted on the anode side shell (20) and the cathode side shell (21), and the anode side shell (20), the cathode side shell (21) and the electrolytic cell cover plate (22) are butted together through an inner concave seam (36) when the three are connected to each other.

5. The integrated technology and device for electro-reduction based on chemical absorption method according to claim 4, characterized in that: A plurality of anode electrode openings (39) are provided on the front side wall of the anode side housing (20), and a plurality of cathode electrode openings (38) are provided on the rear side wall of the cathode side housing (21). An anode connector (45) is provided at one end of the anode electrode plate (44), and an electrode plate hole (43) is provided at the other end. The anode connector (45) of the anode electrode plate (44) passes through the anode electrode opening (39). A cathode connector (42) is provided at one end of the cathode electrode plate (41), and an electrode plate hole (43) is provided at the other end. The cathode connector (42) of the cathode electrode plate (41) passes through the cathode electrode opening (38). The anode connector (45) is connected to the anode of an external pulse power supply, and the cathode connector (42) is connected to the cathode of the external pulse power supply.

6. The integrated technology and device for electro-reduction based on chemical absorption method according to claim 5, characterized in that: Corresponding to the front, back and upper sides of each ion exchange membrane (28), a plurality of membrane slits (37) are provided on the anode side housing (20), the cathode side housing (21) and the electrolytic cell cover plate (22).

7. The integrated technology and device for electro-reduction based on chemical absorption method according to claim 4, characterized in that: The anode side housing (20), the cathode side housing (21) and the electrolytic cell cover plate (22) are all connected via fasteners (25).

8. The integrated technology and device for electro-reduction based on chemical absorption method according to claim 4, characterized in that: A plurality of the electrolytic cells (4) are connected in parallel to form an integrated electrolytic cell, which is arranged between the front-cell buffer tank (3) and the rear-cell buffer tank (5).

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